The present invention relates to an apparatus for controlling a vehicle having an automatic transmission system, and more particularly to a controlling apparatus for a vehicle having an electronically controlled type automatic transmission system including a gear transmission.
In the conventional control apparatus for a vehicle equipped with an electronically controlled type automatic transmission system employing a gear transmission and a clutch, in order to prevent killing of the engine the clutch is controlled so as to be disengaged when the degree of depression of an accelerator pedal becomes less than a prescribed level and the engine speed is close to its idling speed.
In heavy traffic, however, it is sometimes necessary to drive a vehicle at low speed with the accelerator pedal released, in order to lighten the burden on the driver or to regulate the vehicle speed. This may be possible when the vehicle is in a low gear position because the output torque is large enough to drive the vehicle. However, safety problems may arise if this mode of driving is allowed under all types of operation. On a snowy road, for example, the wheels may spin when the accelerator pedal is depressed to start the vehicle and it may become impossible to get the vehicle moving. In this case, if the clutch does not disengage when the accelerator pedal is released, the wheels will continue to gain and dig more deeply into the snow. As a result, the vehicle will become stuck in the snow.